From £17,724
Ivision Construction are here to help customers who need an Extension Builder in SL1. We offer a competitive rate to complete all your extension bu...
From £17,892
Need to find an Extension Builder near you for all your extension buildering work?
RAM Builders provides a local, trusted extension builder...
From £17,868
Need an Extension Builder in SL1? N H Building Services has been helping local clients (20 mile radius) with their extension buildering jobs for ma...
From £17,404
Need to find an Extension Builder near you for all your extension buildering work?
Kaz Construction Ltd provides a local, trusted extension...
From £17,700
Need an Extension Builder in SL1? BK Builders has been helping local clients (20 mile radius) with their extension buildering jobs for many years. ...
From £17,388
M P Builders is a trusted extension builder serving customers in SL1 and the surrounding area. Contact us to today to get a competitive quote for e...
From £17,636
LSM Roofing are here to help customers who need an Extension Builder in SL1. We offer a competitive rate to complete all your extension buildering...
From £17,948
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,876
Avenue92 is an established extension buildering business in SL1. We come highly recommended and provide competitive quotes for your work.

Underpinning ranges from £16,916 (Jeet & jarmal based in SL1) to £17,948 (A & M MCGILL BUILDING SERVICE based in SL1), but the final cost will depend on the method of underpinning used, how much of your foundations need underpinning and where you live.
Comparing extension builders estimates for underpinning gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
Get quotes to underpin your home in SL1 by posting a job with HaMuch and we will send it to extension builders in SL1.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Slough | £36 | £238 |
| Underpin A Building near Windsor & Maidenhead | £36 | £238 |
| Underpin A Building near Windsor | £36 | £238 |
| Underpin A Building near Maidenhead | £36 | £236 |
| Underpin A Building near Gerrards Cross | £37 | £244 |
| Underpin A Building near Egham | £36 | £228 |
| Underpin A Building near Staines-upon-Thames | £36 | £231 |
| Underpin A Building near Hillingdon | £56 | £240 |
| Underpin A Building near Ascot | £35 | £237 |
| Underpin A Building near Bracknell Forest | £35 | £248 |
Whether you’re looking to extend your kitchen with a side return extension or you want to convert your basement into a liveable space, read our cost guides to get an idea of how much each project costs before getting a more accurate quote from our database of reliable tradespeople.

Underpin a building - £17,635

Two storey extension - £88,203

Build a timber frame extension - £26,135

Build a swimming pool - £81,135

Single storey extension - £57,704

Side return extension - £43,021

Install an RSJ - £2,335

Outbuilding - £10,135

Build a Mansard loft conversion - £52,135

Loft conversion - £35,018

Build a kitchen extension - £42,135

Hip to gable loft conversion - £42,135

Granny annexe - £87,135

Garden office - £10,135

Convert a Garage - £16,135

Garage - £18,635

Build a flat roof extension - £22,135

Build a dormer loft conversion - £42,135

Concrete foundations - £6,385

Convert a bungalow loft - £29,135

Convert a basement - £39,021